Nematicidal activity of powder and extracts of Inula viscosa

The number of second-stage juveniles of Meloidogyne javanica in sand was greatly reduced by mixing in leaf powder of Inula viscosa at a concentration of 0.1% (w/w). Powder from other plant parts, except the root, also showed nematicidal activity. Fresh shoots incorporated into the sand showed less of a nematicidal effect. An aqueous extract of the leaf powder exhibited slight nematicidal activity against the nematode, whereas its extracts with organic solvents showed stronger activity. M. javanica was most sensitive to the leaf powder, followed by Tylenchulus semipenetrans, while Aphelenchus avenae, Ditylenchus dipsaci and Pratylenchus mediterraneus were much less, or not at all affected. Acetone extracts of the fresh and dry leaves yielded two fractions with nematicidal activity by column chromatography. One nematicidal fraction contained a mixture of costic and isocostic acid. This mixture, presumably located in the outside of the shoots, showed nematicidal activity toward M. javanica at a concentration of 50 mg/kg sand.